1. Field of the Invention
The present invention relates in general to a suction and exhaust connection device for multi-cylinder internal combustion engines and, more particularly, to a structural improvement in such a suction and exhaust connection device for converting the detonation exhaust pressure of a cylinder in an exhaust stroke into a suction pressure of another cylinder in a suction stroke synchronous with the exhaust stroke of one cylinder thereby increasing both the suction speed and amount, and for temporarily keeping the suction gas therein just after a suction stroke of the other cylinder and letting the suction gas be sucked into the other cylinder at a high speed in the next suction stroke of the other cylinder, thereby restricting the suction interference and increasing the suction amount, and for temporarily keeping a part of the exhaust gas therein during the exhaust stroke of the one cylinder and expelling the temporarily kept exhaust gas to the outside after a predetermined time, thereby restricting the exhaust interference and letting the continuous exhaust of the exhaust gas and reducing the exhaust noise of the engine.
2. Description of the Prior Art
In conventional multi-cylinder internal combustion engines for automobiles, suction and exhaust efficiency of the engine is an important factor largely affecting both engine output and rate of fuel consumption. In internal combustion engines, the suction stroke for drawing a fresh gas mixture or a suction gas into a cylinder is achieved by negative pressure formed in the cylinder due to a downward movement of a piston in the cylinder, while the exhaust stroke for expelling the detonation exhaust gas from the cylinder is achieved by positive pressure formed in the cylinder due to an upward movement of the piston in the cylinder and due to the remaining combustion pressure in the cylinder. Meanwhile, the remaining combustion pressure of the cylinder is considerably high, so that the exhaust gas, which is expelled from the cylinder into the exhaust port the moment the exhaust valve is opened, flows at a high pressure, a high temperature and at a high speed exceeding the speed of sound. However, the negative pressure formed in the cylinder due to the downward movement of the piston is just slightly higher than the positive pressure of the cylinder in the exhaust stroke and, furthermore, the suction resistance is increased when the suction gas passes through the air filter and through the suction line. Therefore, it is difficult to supply a sufficient amount of mixture gas for the cylinder.
In order to improve the engine efficiency of the internal combustion engine, the high temperature, high pressure exhaust gas should be rapidly expelled from the cylinder during the exhaust stroke to the outside and the fresh gas mixture should be sucked into the cylinder during the suction stroke.
Another problem of the typical suction and exhaust device of the internal combustion engine is that a part of the fresh gas mixture strikes against the suction valve and flows in a reverse direction when the suction valve is closed just after the suction stroke. The reverse flow of the fresh gas mixture interferes with the fresh gas mixture sucked into the cylinder in the next suction stroke and the interference of the fresh gas mixture reduces engine output. When the high temperature, high pressure exhaust gas, which is expelled from a cylinder through the exhaust port during the exhaust stroke of the cylinder, remains in the exhaust manifold or in the exhaust pipe, the exhaust gas remaining in the exhaust manifold or in the exhaust pipe interferes with the exhaust gas expelled from another cylinder. Such interference of the exhaust gas not only causes vibration and engine noise, but also deteriorates the exhaust efficiency of the engine.